1. Field of the Invention:
This invention relates to trailers, and, more particularly, to trailers secured to tractors for transporting loads.
2. Description of the Prior Art:
U.S. Pat. No. 4,397,476 (Bolyard et al), U.S. Pat. No. 4,561,671 (DeWitt et al) and U.S. Pat. No. 4,566,714 (DeWitt et al) all disclose trailers with movable frame assemblies. The three patents are similar in that the length of the trailer is varied in each patent by a single telescoping element. However, the apparatus of the '476 patent does not transfer a fixed load weight, but merely telescopes for transporting and storing purposes. The apparatus of the '671 and '714 patents change trailer lengths for the purpose of accommodating a container of different lengths.
There are other patents which discloses a fixed frame and a movable frame utilizing sliding elements.
U.S. Pat. No. 3,682,419 (Wolf) is one example of trailer apparatus including movable trailer portions. The '419 patent discloses a trailer apparatus in which the length of the trailer remains constant, but the rear wheel and axle portion is movable between two locations. The movable rear wheel and axle portions do not extend beyond the fixed frame, and thus do not extend beyond the trailer load.
U.S. Pat. No. 2,831,700 (Sheppard et al) discloses a locking system for locking the rear axle and wheel assembly of a trailer. As in the '419 patent, the trailer length is fixed and the rear wheel and axle portion is movable or variable between a plurality of locations. The slidable wheel and axle portion is not a load supporting frame assembly, and does not extend beyond the load bearing frame or the load.
U.S. Pat. No. 2,831,735 (Bennett et al) discloses another trailer apparatus in which the trailer length itself is fixed, but the location of the rear wheel and axle unit is longitudinally adjustable. Details of the adjusting elements, including the locks, are specifically claimed. Again, the rear wheel and axle unit is not a load supporting frame assembly and does not extend beyond the load bearing frame.
U.S. Pat. No. 2,835,504 (Acker) discloses still another example of a trailer having a fixed length with a movable rear axle system. The apparatus is primarily concerned with the control system and the locking system for the trailer apparatus. And again, the movable wheel and axle assembly is not a load bearing frame assembly and it does not move beyond the load carrying frame.
U.S. Pat. No. 2,841,411 (Sheppard et al) discloses apparatus similar to the '700 apparatus discussed above. It will be noted that both patents have the same inventors. The locking system for the rear wheel and axle assembly is described and claimed in detail. As with the above-discussed patents, the movable wheel and axle assembly is not a load bearing frame assembly and it does not move outwardly beyond the load bearing frame.
U.S. Pat. No. 3,146,000 (Holtzman) discloses another system in which the general length of the trailer itself is fixed, and the wheel and axle assembly moves relative to the frame. Several roller systems for adjusting the running gear or wheel and axle assembly are shown. Again, the load bearing frame is fixed, and the movable portion does not extend beyond the fixed, load bearing frame.
U.S. Pat. No. 3,410,576 (Turpen) discloses a reversible tandemaxle semitrailer. There is a single semitrailer with a pair of wheel and axle assemblies that are movable between the front and the rear of the semitrailer so that the semitrailer may be pulled from either end. The semitrailer includes two hitch elements, one hitch element at each end of the trailer. The wheel and axle elements are individually movable to position each axle in a desired location with respect to the trailer. Both axles may be positioned adjacent to each other at opposite ends of the trailer or one axle may be positioned near the center while the other axle may be positioned at the rear, as desired, depending on the particular load being hauled on the trailer. The load bearing frame is fixed and does not vary.
U.S. Pat. No. 3,508,762 (Pratt) discloses an extendable trailer system in which the frame itself is actually lengthened. The apparatus includes a fixed frame having I beam elements and tubular elements which telescope on the I beams. Rollers are required between the I beams and the tubular elements. The load itself rides on the moving elements. The frame members accordingly must be moved and fixed in place before the load is placed on the frame members.
U.S. Pat. No. 4,111,450 (Pinto) discloses a trailer having the capacity to connect to a tractor at both ends. At the bottom of the trailer sides, and inwardly from the outer ends of the trailer, are a pair of longitudinally extending rails which comprise eye beams. The eye beams comprise fixed rails secured to the trailer bed. There are extension rails that may be aligned longitudinally with the fixed rails. The rail extensions will fit both ends of the trailer to allow trailer wheel and axle assemblies to be positioned as desired with respect to the trailer. For connecting the trailer to a tractor from one end, the rail extensions are disposed at the opposite end of the trailer, and wheel and axle assemblies are appropriately secured to the rails and rail extensions. No part of the sliding or movable portion extends beyond the main frame.
The '450 apparatus also includes provisions for connecting a pivotable or steerable axle to the trailer through a movable or slidable kingpin assembly. For purposes of the apparatus of the present invention, the movable kingpin assembly and steerable axle elements are immaterial.
U.S. Pat. No. 4,365,820 (Rush) discloses a trailer which includes movable running gear so as to connect a plurality of trailers in tandem through fifth wheel assemblies secured to the running gear. The running gear includes a pair of axles, both of which are secured to longitudinally extending frame members. The flanges of the vertically and longitudinally aligned eye beams bear directly against each other and channel lengths secured to the lower of the eye beam pairs are used as guide elements. No provision is made for lubricants. The apparatus is not designed for, and has no applicability to, bridge laws and the distribution of load weights.
U.S. Pat. No. 4,478,547 (Den Boer) discloses an extensible trailer system with multiple portions. The apparatus has no applicability to bridge laws or to the distribution of load weights.
U.S. Pat. No. 4,526,395 (Arguin) discloses a tandem trailer system with a movable slider portion that includes a fifth wheel assembly for securing a second trailer in tandem with the first trailer that is connected directly to the tractor. The movable slider portion of the trailer, that portion which includes the fifth wheel, is disclosed as including three sets of wheel and axle pairs. The movable frame is movable on a pair of vertically oriented I beams and is appropriately secured together by a channel element secured to the bottom beam member. Direct contact between the adjacent flanges of the beams is prevented by means of an insert or slide pad. Slide pads are appropriately secured to the bottom of the lower flange of the upper I beam. The I beam assemblies are locked together by appropriately actuable pins which extend through aligned apertures in locking plates and in the vertical flange of the upper beam.
The purpose of the sliding undercarriage or chassis portion is not to extend the length of the trailer bed for bridge law purposes, but rather simply to facilitate the tandem pulling arrangement of a pair of trailers by a single tractor. This is also the primary purpose of the '820 patent discussed above. The sliding undercarriage apparently cannot be moved with a load on the trailer. No provision is made for lubrication because lubrication does not appear to be necessary.
U.S. Pat. No. 4,580,805 (Bertolini) discloses an extensible trailer system which utilizes a rack and pinion system for moving the trailer frame portions. Roller chain dollies on the movable frame roll on fixed flanges of the fixed frame. The movable frame axles do not extend rearwardly of the fixed frame.
U.S. Pat. No. 1,627,336 (Nelson) discloses a dump body in which the dump bed tapers from the front to the rear. The dump body is narrowest at the front end, and tapers outwardly or flares outwardly to the widest portion at the outer end, where material is dumped. In addition to the tapering of the bed from the front outwardly, the sides of the bed also include a taper. The taper is narrowest at the top and the walls taper outwardly to the bottom of the bed. At the outer end of the trailer, the walls are substantially vertical. Thus, the taper of the walls varies from maximum taper at the front of the trailer bed to virtually zero or vertical alignment at the outer end of the dump bed. The bottom of the bed is flat or planar over its entire length.
U.S. Pat. No. 3,152,837 (Margala) discloses a combination dump trailer that includes a pair of dump portions on a single chassis. Essentially, the dump portions comprise separate dump beds disposed on a single chassis. The undercarriage of the single bed is movable between two positions so that the tractor may be connected to both ends of the trailer to facilitate the dumping. The movable undercarriage has no applicability to bridge laws, and the movable frame does not extend beyond the fixed frame. The guide elements are relatively short, and they do not extend over even a substantial length of the movable frame.
A single cylinder is used for dump purposes. The single cylinder, in the center of the trailer chassis, is selectively securable to both dump beds for appropriate pivoting movement to dump the contents of the dump beds.
U.S. Pat. No. 3,181,914 (Humes) discloses a dump trailer assembly which includes a sliding undercarriage. The undercarriage moves for purposes of complying with appropriate bridge laws. The undercarriage includes a fixed eye beam assembly and a lower eye beam assembly, but the eye beam assemblies do not move on each other during movement of the sliding undercarriage. Rather, there are roller assemblies on which the undercarriage moves while moving between the inner and outer positions of the undercarriage. Locking supports required at both positions of the sliding undercarriage. Guide elements are relatively short. Only one axle extends beyond the fixed frame. The second axle remains beneath the fixed frame.
U.S. Pat. No. 4,021,074 (Heiser) discloses a vehicle trailer designed to be pulled by a pickup truck. The trailer and pickup truck utilize a fifth wheel connection. The dump bed portion of the trailer includes a sloping bottom or bed. The purpose of the sloping bottom is for convenience in design, to allow the dump trailer to be pulled by a pickup truck, as opposed to convenience in dumping the load from the trailer. Obviously, the sloping bottom will facilitate the dumping, but such is not the purpose of the sloping bottom. Moreover, the bottom has only a single slope. With a single slope, the load could shift during transit and significant problems could arise therefrom.
French Patent No. 1,464,476 (Richebois) discloses a dump trailer which includes tapering side walls. The width of the dump bed tapers outwardly from a minimum at the front of the trailer to a maximum at the rear or tailgate of the trailer. The bottom of the trailer appears to be relatively flat. The sides appear to be relatively vertical, with rounded or coved portions between the sides and the bottom. The height of the sides vary from maximum at the front of the bed to minimum at the rear of the bed.
It will be noted that of the patents discussed above that include slidable undercarriages, the forward axle of a pair of axles that slide is never found outboard of the trailer itself. One axle of a pair of axles may extend rearwardly from the primary trailer frame, but one axle is always shown beneath the rear portion of the primary trailer frame. Moreover, it will also be noted that the patents are noticeably silent regarding the sliding characteristics of the movable frame assemblies, particularly with respect to lubrication and/or cleaning of the relatively movable elements.
The apparatus of the present invention overcomes the problems or limitations of the prior art by providing a sliding undercarriage which accommodates current bridge laws and which includes axle assemblies outwardly from, or to the rear of, the rear most portion of the primary or fixed trailer frame and which provides for the cleaning and lubrication of the relatively movable frame members.